[vtkusers] flipping the scene:(Parity Transform)

[Fletcher, Bob (GEAE)]

I have a scene with many actors. I need to flip the whole scene around,
replacing z with -z. (Parity Transform).

I tried 
myactor  SetScale 1 1 -1

The geometry looks ok, but it's all rendered flat black. Without the
Setscale it's colored by it's scalar value.  Is this some kind of normal
vector problem? 

I can setScale -1 -1 1, and the colors are ok, but of course it doesn't
change my geometry!

Is there a better approach? This seemed simplest.  Is ther a Left
handed/righthanded corrdinate system flag hiding someplace?

Any thoughts?

Bob.